Automotive vehicle body structures often include assemblies such as spoilers, closure panels, fenders, and the like that have complementary inner and outer panels that are joined at peripheral surfaces. In one joining approach, one or both of the panels to be joined has an adhesive channel formed in it to promote the delivery of an adhesive. When bonding such automotive structures, an undesirable appearance known as a bond-line read through can occur when the thickness or width of the adhesive joint is too large. A continuing difficulty arises in that when bonding the inner and outer panel members together over-filling or under-filling the adhesive channel results in reduced bond strength or appearance defects.
Another bonding method exists wherein neither joined surface includes an adhesive channel. In this configuration, a free standing adhesive bead is dispensed directly onto a flat surface of one of the panels. With this and other bonding methods, great care and precision must be exercised to avoid the appearance defects that are caused by the shrinkage of the adhesive during curing. Such additional effort is time consuming and expensive. Thus, the avoidance or repair of such defects has been a continuing problem for automotive manufacturers.
There remains a need to address the adhesive bonding of plastic panels or other parts having surface appearance requirements in order to improve bond joint quality and robustness.